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In this work, a review of recent studies concerning rare nuclear processes in Hf isotopes is presented. In particular, the investigations using HP-Ge spectrometry and Hf-based crystal scintillators are focused; the potentiality and the results of the “source = detector” approach are underlined. In addition, a short introduction concerning the impact of such kind of research in the context of astroparticle and nuclear physics is pointed out. In particular, the study of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>α</mi></semantics></math></inline-formula> decay and double beta decay of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>174</mn></msup></semantics></math></inline-formula>Hf, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>176</mn></msup></semantics></math></inline-formula>Hf, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>177</mn></msup></semantics></math></inline-formula>Hf, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>178</mn></msup></semantics></math></inline-formula>Hf, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>179</mn></msup></semantics></math></inline-formula>Hf, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>180</mn></msup></semantics></math></inline-formula>Hf isotopes either to the ground state or to the lower bounded levels have been discussed. The observation of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>α</mi></semantics></math></inline-formula> decay of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>174</mn></msup></semantics></math></inline-formula>Hf isotope to the ground state with a T<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>=</mo><mn>7.0</mn><mrow><mo>(</mo><mn>1.2</mn><mo>)</mo></mrow><mo>×</mo><msup><mn>10</mn><mn>16</mn></msup></mrow></semantics></math></inline-formula> y is reported and discussed. No decay was detected for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>α</mi></semantics></math></inline-formula> decay of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>174</mn></msup></semantics></math></inline-formula>Hf isotope at the first excited level of daughter and of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>176</mn></msup></semantics></math></inline-formula>Hf, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>177</mn></msup></semantics></math></inline-formula>Hf, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>178</mn></msup></semantics></math></inline-formula>Hf, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>179</mn></msup></semantics></math></inline-formula>Hf, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>180</mn></msup></semantics></math></inline-formula>Hf isotopes either to the ground state or to the lower bounded levels. The T<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub></semantics></math></inline-formula> lower limits for these decays are at the level of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>16</mn></msup></semantics></math></inline-formula>–<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>20</mn></msup></semantics></math></inline-formula> y. Nevertheless, the T<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub></semantics></math></inline-formula> lower limits for the transitions of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>176</mn></msup></semantics></math></inline-formula>Hf<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mspace width="3.33333pt"></mspace><mo>→</mo><msup><mspace width="3.33333pt"></mspace><mn>172</mn></msup></mrow></semantics></math></inline-formula>Yb (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mn>0</mn><mo>+</mo></msup><mo>→</mo><msup><mn>0</mn><mo>+</mo></msup></mrow></semantics></math></inline-formula>) and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>177</mn></msup></semantics></math></inline-formula>Hf<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mspace width="3.33333pt"></mspace><mo>→</mo><msup><mspace width="3.33333pt"></mspace><mn>173</mn></msup></mrow></semantics></math></inline-formula>Yb (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>7</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup><mo>→</mo><mn>5</mn><mo>/</mo><msup><mn>2</mn><mo>−</mo></msup></mrow></semantics></math></inline-formula>) are near to the theoretical predictions, giving hope to their observation in the near future. All the other experimental limits (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>∼</mo><msup><mn>10</mn><mn>16</mn></msup></mrow></semantics></math></inline-formula>–10<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>20</mn></msup></semantics></math></inline-formula> y) are absolutely far from the theoretical expectations. The experiments investigating the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2</mn><mi>ϵ</mi></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ϵ</mi><msup><mi>β</mi><mo>+</mo></msup></mrow></semantics></math></inline-formula> processes in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>174</mn></msup></semantics></math></inline-formula>Hf are also reported; the obtained half-life limits are set at the level of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>16</mn></msup></semantics></math></inline-formula>–<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>18</mn></msup></semantics></math></inline-formula> y. Moreover, we estimate the T<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub></semantics></math></inline-formula> of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2</mn><mi>ν</mi><mn>2</mn><mi>ϵ</mi></mrow></semantics></math></inline-formula> of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>174</mn></msup></semantics></math></inline-formula>Hf decay at the level of (0.3–6) × <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>21</mn></msup></semantics></math></inline-formula> y (at now the related measured lower limit is <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>7.1</mn><mo>×</mo><msup><mn>10</mn><mn>16</mn></msup></mrow></semantics></math></inline-formula> y).